This invention relates to a process of producing semiconductor devices and more particularly mesa type semiconductor devices.
It is well known that selectively etching processes used in the planar technique can be applied to the production of mesa type semiconductor diodes in order to increase the efficiency thereof. Conventional selective etching processes have been disadvantageous in that one portion of the semiconductor wafer located under each edge of a protective film involved is undercut to form an acute angle and that the sharp edge portion of the wafer thus formed can not be sufficiently covered with a photoresist layer for the subsequent photolithographic process, as well as being easily damaged. Thus that portion of a surface passivation film disposed on the sharp edge portion of the wafer has been etched away in the photolithographic process. Alternatively the sharp edge portion of wafer might be chipped. This has resulted in the surface stabilization being unsatisfactory.